Portable impact tool assemblage



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S. MANDL ET AL PORTABLE 'IMPACT TOOL ASSEMBLAGE March 7, 1950 Filed July21, 1945 @w mw NW bmw f MN @E E mm,

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PORTABLE IMPACT TOOL ASSEMBLAGE` Filed July 21, 1945 2 Sheets-Sheet 2 32I' 1". /7 l L A wo f6 58 In `57 37 50 ,5

f 4 .4. /3 ,9 :j /2 -f-T'E" 46 47- f l INVENTORS f3' Mw l ATTO/@NavaPatented Mar. 7, 1950 PORTABLE IBIPACT TOOL ASSEMBLAGE Siegmund Mandl,Milwaukee, and Edward M.

Pfauser, Elm Grove, Wis., assignors to Blackhawk Mfg. Co., Milwaukee,Wis., a corporation of Wisconsin Application July 21, 1945, Serial No.606,442

3 Claims.

Our invention relates generally to improvements in impact tools, andrelates more specically to improvements in the construction andoperation of portable reciprocatory impact tool assemblages forperforming various classes of work, and especially adapted to dress softmetals.

The primary object of the present invention is to provide a new anduseful portable impact tool assemblage which is simple `and compact inconstruction and highly eficient in operation.

Considerable difliculty has heretofore been encountered when attemptingto use rasps or other well known types of files for the purpose offiling soft metals such as lead, babbitt, zinc, or the like, because ofthe fact that the removed particles of material would lodge in the teethof the reciprocatory tool and would thus cause the le to merely slideover the work without functioning to remove subsequent metallicparticles. While this objectionable action resulted to some extent bothwhen manipulating the les rather slowly by hand, and when utilizing morerapid power actuation, it was far more pronounced when operating therasps at high speed and with uniform reciprocations or strokes in bothdirections, and in such cases the teeth would clog after but a fewrecipro-cations and the tools would become useless without frequentstopping and cleaning. We have discovered that this annoyance may beentirely and effectively eliminated by properly constructing the teethof the rasp or file in the form of a series of chisel edges, and byapplying a rapid succession of reciprocatory impacts rather than uniformreciprocations, to the toothed tool, whereby each chisel tooth edge willquickly shave particles of material from the work during the rapidforward stroke thereof but will shed the removed material from itscutting edge during the slower return stroke of the tooth. We have alsofound that in order to successfully apply this principle of operation toa portable file, the relatively light tool must be suspended from acomparatively heavy body or support, in order to insure most effectivework performance.

It is therefore a more specific object of our present invention toprovide an improved reciprocatory rasp or toothed implement, and animproved carrier for actuating the same, whereby the assemblage may beutilized to effectively perform most difcult classes of work.

Another specific object of this invention is to provide an improvedportable impact tool and support especially adapted for use in dressingor filing soft metals such as lead, babbitt, Zinc, copper, brass, or thelike, and which may be operated for prolonged periods of time withoutnecessity of cleaning or sharpening the teeth or cutting edges of theimplement.

A further specific object of the invention is to provide an improvedportable mechanism for applying a rapid succession of reciprocatoryimpacts to various types of les or other impact tools, in a mosteiicient manner and without permitting the tool to be pushed back by thefixed work during each impact stroke.

Still another specic object of our invention is to provide a simple,compact, and durable power operated portable impact tool assemblage,which is flexible in its adaptations and which is also adapted to befreely manipulated in any desired direction and in corners and otherrelatively inaccessible localities.

An additional specific object of the present invention is to provide animproved portable impact unit, all parts of which are normally amplylubricated and protected While still being conveniently accessible andremovable, and which may be manufactured at moderate cost and utilizedfor diverse purposes.

These and other specific objects and advantages of the invention will beapparent from the following detailed description, and some of theimproved features of portable tool actuating unit construction shown butnot specifically claimed herein, form the subject of co-pendingapplications.

A clear conception of the several features constituting our presentinvention, together with the mode of constructing and of manipulatingour improved tools and driving units, may be had by referring to thedrawings accompanying and forming a part of this specification whereinlike reference characters designate the same or similar parts in thevarious views.

Fig. 1 is a longitudinal central section through one of our improvedportable impact tool assemblages including a rasp and mechanism fordriving the same;

Fig. 2 is a bottom View of the improved assemblage of Fig. 1, with thefront manipulating knob omitted;

Fig. 3 is a front end view of the improved impact tool assemblage;

Fig. 4 is a transverse section through the improved assemblage, takenalong the line l-ll of Fig. l;

Fig. 5 is another transverse section through the same assemblage, takenalong the line 5 5 of Fig. 6 is still another transverse section throughthe assemblage, taken along the line 6-6 of Fig. 1; and

Fig. '7 is a side elevation of the rotary driven member of the improvedassemblage.

While the invention has been shown and described herein as beingadvantageously applicable to a portable impact tool assemblagecomprising an improved rasp or le and mechanism operable from a remotesource of power -for converting rotary motion into reciprocatory impactmovement and for delivering the latter to the improved tool, it is notour desireto unnecessarily limit the improvement by virtue of lthisspecific embodiment, as some of the improved features are obviously moregenerally applicable to impact tools and operating mechanisms therefordriven by various types of motors disposed either ,remotely from ormounted directly upon the portable unit. It is also intended thatvarious specific terms employed herein in order to clearly dene thestructure, be given the broadest possiblemeaning and interpretationconsistent withthe prior art.

Referring to the-drawings,the improved portable impact tool andoperating assemblage shown therein by way of illustration, comprises ingeneral, an upper elongated casing or body I having a central bore II; alower similarly elongated casing or base I2 also having a central boreI3 and coacting through an intervening sealing gasket I4 with the lowerflat surface of the body I; an elongated special le or rasp I5 carriedby an L -shaped sled or bracket I6 which has sliding coaction with aplane bearing plate I1 secured to the lower flat surface of the base I2;a hammer or impact element i8 slidably conned within the base bore I3and cooperating at one end with a stiff impact producing spring I9 andat its opposite end with a plunger 2G secured to the rasp carryingbracket IG; a rotary driven member 2I conned within the body bore I Iand having one or more revolving cam surfaces22 and drop-olf *ledges 23which are-cooperable with a tapered roller 24 carried by a lateralprojection 25 firmly secured to the element E8 to retract the latterafter each impact movement produced by the spring ISI; a hollow plug/28normally rigidly conned within the open end of the body bore II andhaving an integral tubular rear extension 21; a sleeve 28 slidablyand-rotatably confined within the plug 26; a rotary driving member 29jourf nalled for rotation within the sleeveZB in axial alinement withthe driven member 2l and having a polygonal end projectioni which iscooperable with a star-shaped socket'SI formed in tubular element'SZcarried by the member 2l to establish a rotary driving connection'between'the members 2S, 2|; a `flexible drive shaft 33"for the drivingmember 29 adapted to be constantly rotated from any suitable source ofpower; a rear manipulating handle 34 embracing the tubular plugextension21 and the power delivery end of the shaft 33; and a front manipulatinghandle or knob 35 secured-to the upper forward vend of thecasing bodyIll.

The upper casing or body IB and r'the lower casing or base I2 are firmlybut detachablyA united by screws 3S which also clamp'the gasket ill inplace, and these united casings I9, I2l should be relatively heavy inorder to vprovide a portable body the inertia of which will effectivelyresist rearward thrust induced .by Vthe comparatively .light le or othertool, 1 during eachfimpact stroke. The I -shaped tool carrying sled Yorbracket lSlwhich slidably engages' thelower bearing plate I1, coactswith a rear end guide 31 `cated in Figs. 1 and 2. teeth 5G is preferablyconvex in the direction of secured to the casings I0, II by means oflonger screws 38, and these screws 38 also serve to hold the plate I1 inproper position and to additionally firmly but detachably unite the maincasing sections. The front leg of the sled bracket i5 is secured to theAouter extremity of the plunger 20 by a cap screw 39 and lock washer 40;and the medial portion of this plunger 2D is provided with a flange 4|which is slidable within a reduced portion of the bere I3. The forwardportion of the plunger 2E) is embraced by a relatively light compressionspring 42 which coacts with the base I2 and with the flange il toconstantly urge the sled I5 rearwardly, and the front leg of the sledbracket I5 is cooperable with a stop washer 43 so as to limit the returnstroke of the sled and rasp I5. The rear portion of the plunger 2U isembraced by a resilient buffer 44 and is of polygonal cross-section asshown in Figs. 1 and 4; and the 'front end vof the impact hammer orelement I8 has therein a polygonal socket 45, which slidably 'engagesthe rear end portion oi the plunger 2D and prevents relative rotation ofthe hammer and plunger. The stiff impact producing spring I9 whichengages the rear end of the hammer I8, reacts against an adjustable plug46 which is screw threaded within the bore I3 of the casing 4base I2,and is adapted to be locked in various positions of adjustment by a pin41 coacting with any of a series of holes 48 formed in the casingsection I2.

While various types of reciprocatory impact tools may be applied to thesled or bracket IS, we have found thatthe improved rasp I5 is especiallyadvantageous when utilized to le soft metals. This rasp l5 which isrelatively lght as compared to its portable suspension body, is firmlysecured to the lower elongated leg of the sled bracket i5 by fusion ofmetal as by welding or brazing and with the additional aid of rivets orscrews 49; and is provided with a series of transversely curved chiselteeth 56 as clearly indi- The curvature of the the impact blows, thatis, the mid-portions of the teeth are farthest advanced in the directionof travel of the rasp I 5 during its forward or cutting proximatelyperpendicular to the plane of the rasp I5, while the rear faces of theteeth are inclined rearwardly and upwardly -toward this plane, thusavoidingundercut pockets or ledges within which chips or particles mighttend to lodge, while still providing sharp cutting edges -or successivechisels.

As previously indicated, this improved rasp I5 has proven highlysatisfactory and effective in actual use on soft metals such as lead,zinc, babbitt, brass, aluminum,

and the like, when operating at speeds as high as three thousandimpactsV per minute.

The impact buffer 44 is preferably formed of lsoft rubber or rubber andcanvas disks which also serve as seals, and the-plunger25 isadditionally embraced by apacking 5I lwith which the spring -ll2 Vcoactsso as to aid the gasket I4 in sealing the bore I3 within which'thehammer I8 is confined. The bores il, I3 of the two casings Ill, I2coml'municate with-eachother through alined slots 52 along which'theerilargedfmedial portion 53 of the motion transmitting projection 25is slidable in order to maintain the tapered roller 24 in propercoaction with the cam surfaces 22 of the driven member 2| at all times,and to also assist the polygonal socket in preventing possible rotationof the hammer element i9. While the enlarged medial portion of therotary driven member 2| which is confined within the upper casing borei, is shown in Figs. 1 and 7 as having only one helical or cam surface22 and dropoff surface 23, formed thereon, whereby only a single impactmovement is produced during each revolution of the member 2|, thissingle surface 22 may obviously be replaced by a member 2l havingseveral successive cam surfaces 22 and drop-oi ledges interconnectingthe adjacent ends of the successive cams, in order to produce a numberof impacts during each revolution of the driven member. The rotarydriven member 2| which should be dynamically balanced, is journalled forfree rotation in front and rear anti-friction thrust-resisting bearings54, respectively, confined within the bore I| and coacting with areduced end portion 53 of the member 2| and with the tubular socketedelement 32, and these bearings are formed to prevent axial displacementof the member -2|. The front lbearing 54 coacts with the inner end ofthe bore while the rear bearing 55 is engaged by a bushing 51 which isscrew threaded within the outer end portion of the bore and a packingassemblage 58 coacts with the bushing 51, bearing 55, and element 32,and cooperates with the gasket I4, buffer 44, and packing 5| to confinelubricant within the casing bores i3.

The interior of the rotary driven member 2| and the central bore of thetubular element 32, are provided with a compression spring 59 and aplunger 69 disposed in axial alinement with the rotary driving member29, and this spring and plunger tend to constantly interrupt the drivingconnection afford-ed by the projection 30 and socket 3|, as indicated inFig. 1. In order to avoid such interruption of this driving connectionwhen the tool is being operated, the bearing sleeve 28 in which therotary driving member 29 is journalled, is provided with an annulargroove 6| with which a latch 62 is cooperable as illustrated in Figs. 1and 6. Another latch 53 is cooperable with a second annular groove 64also formed in the sleeve 28, when the latch 62 has been released andthe spring 59 and plunger 69 have acted to push the driving projection39 out of the driven socket 3|; and these latches 52, 63 are swingablysuspended from the casing plug 26 by pivot pins 55 and are resilientlyurged toward latching position, by springs 66 and plungers 91, as shownin Fig. 6. When the latch 52 is active, the projection 39 is positivelyheld within the socket 3| and the direct rotary driving connection ismaintained while the other latch 63 is inactive, but if the latch 62 isreleased, the spring 59 and plunger 69 immediately force the projection30 out of the socket 3| to interrupt the driving connection, and thelatch (i3 then engages the groove 66| so as to prevent the bearingsleeve 28 from being pushed out of the casing plug 25. The drivingconnection may however be quickly re-established by merely pushing thesleeve 28 inwardly, and the plug 26 is at all times freely rotatableabout the sleeve 28 and may be readily withdrawn from this sleeve bymerely releasing both latches 62, B3. The plug 26 may be iirmly butdetachably secured to the casing body ID by means of a second bushing 68coacting with the internal screw threads of the casing bore and with aperipheral flange 69 of the plug, and both bushings 51, |58 are providedwith end notches adapted for reception of a spanner wrench.

The driving projection 39 may either be formed integral with the rotarydriving member 29, or secured thereto by means of a shear pin 19, and aspreviously indicated, the member 29 is adapted to be constantly rotatedby a flexible shaft 33 operable from any suitable source of power suchas an electric or fluid pressure operated rotary motor. The powerdelivery end of the shaft 33 may be firmly secured to the driving member29, by fusion of metal or otherwise, and is housed within a flexiblenon-rotating conduit 1| the end of which is rigidly attached to a tting12 screw threaded to the bearing sleeve 28. The fitting 12 and theadjacent end of the :exible conduit 1| may be conned within the integraltubular rear extensin `21 of theplug 25 to which the rear manipulatinghandle Jil is also attached, thus protecting the operator againstcontact with power driven parts; and the rear handle 34 is preferablydisposed in axial alinement with the body I9 while the frontmanipulating knob is preferably disposed at an angle as shown, in orderto facilitate manipulation of the unit in a manner similar to anordinary hand file.

When it becomes desirable to utilize the irnproved power driven portableunit and rasp l5, the upper and lower casing sections lil, l2 should rstbe properly assembled as shown, and the bores i3 should be supplied withabundant and suitable lubricant. The driven member 2|, roller 2li,impact element I5, plunger 29 and the anti-friction bearings 55, 55 willthen be confined in the lubricant and positively protected against entryof dust and grit by the gasket Eli, packing 5|, and sealing assemblage53. The rasp I5 should be rmly attached to the sled bracket l5 with theaid of rivets or screws 49, and by fusion of metals, and this sledshould be caused to slidably coact with the bearing plate I1' and guide31, and should be firmly attached to the outer end of the plunger 29with the aid of the cap screw 39 and lock washer 29. After the tensionof the spring i9 has been properly adjusted with the aid of the plug 43and pin 91, the assembled portable unit may be applied to the bearing'sleeve 28 with the aid of the latch 53 coacting with the groove 64, andthe flexible drive shaft 33 should be constantly rotated at any desiredspeed and from any suitable source of power located either remotely fromthe portable unit or carried directly thereby.

During normal operation and use of the power driven unit, the operatorwill ordinarily grasp the handle 34 and knob 35, and he may provide adriving connection between the projection 39 of the driving member 29and the socket 3| of the driven member 2|, by merely pushing the sleeve28 inwardly with the aid of the conduit 1l until the latch |52 snapsinto the annular groove 6|, but Without manually pressing either latch62, 63. Rotary motion from the driving member 29 will then be imparteddirectly to the driven member 2| thereby causing the cam and ledgesurfaces 22, 23 of this member to revolve about the common axis of themembers 2i, 29, and producing a succession of rapid retractions of theroller 2d, projection 25 and impact element i8. During each of theseretractions of the hammer element i8, the stiff spring i9 which coactswith the hammer and reacts against the relatively heavy casing body, iscompressed and the other "agradece lighter fspring 42 which fcoacts withthe lighter .plunger Zilfexpands, thereby retracting the comparatively:light 'sledA fI16 v"and yrasp \I.5, `:and producing a relatively slowrearward stroke of -the file. 'one of the ledge surfaces 23 after eachyretraction, the stiff spring I9 immediately becomes Yeffective toimpart a rapid vforward or impact `movement to the hammer I8 which inturn delivers each impactto-the rasp l5 and sled I6 'through the plunger26, thereby producing a rapid :succession of forward or impact strokesof the chisel teeth Ell. Whileeach impact stroke of Ithe tool isslightly cushioned by the relatively :light spring d2 coacting with themotion transmitting plunger 29,'about one-fthof each imtpact motion ofthe hammer VI8 is naily absorbed `so as to prevent annoyingvibration,b,v the resilient buffer ill whenever each impact is*completed; and the inertia of the relatively heavy l casings Il), I2veffectively prevents the portable assemblage from being pushedrearwardly by the lighter rasp I5 and sled I6 during the chiselinglormpact strokes.

The rasp I5 is thus subjected to a rapid succession of impact and returnstrokes whenever the driven memberZI is r-being revolved by the drivingmember"29, and the-operator need only hold the assemblage in contactwith the work without undue effort. The chisel teeth 5B remove tparticles of material from the'work during each impact stroke, while theinertia of the heavier body assemblage augments the chiseling action,and the removed particles are ejected from the working zone by thearcuate formation of the teeth 50. The operator may move the portableunit freely over the surfaces of the work in any desired direction andYat any suitable rate of speed, and when it becomes desirable todisconnect the power, it is only necessary to press the latch 62whereupon the spring 59 and the plunger 60 will immediatelybecomeeffective to interrupt the driving connection by forcing the projection30 out of the socket 3l, until the other latch G3 enters the annularrecess 64. latch 63 into the recess'GlI-will'prevent thebearing sleeve28 from being forced out of the bore of theplug 26, but if itbecomesdesirable to remove the portable impactunit from the bearingsleeve 28, both latches 62, 63 may be released whereupon the sleeve 28and the driving member 29 may be freelywithdrawn from within the plug 25and its extension 2. When the sleeve 28 has been thus removed vfrom theportable'unit, thel packing assemblage 58 Will function to maintain aseal for preventing escape of lubricant from within the bores 5I, I3,and ifit becomes desirable to remove the plug 26 and other normallyconcealed parts of the lunit, itis only necessary to remove the bushings51, 68 with the aid of a Spanner wrench, whereupon the plug 26, bearings54, 55 and the rotary driven member 2| may be removed in an obviousmanner. The casing sections Ill, l2 may'bereadily-removed from eachother by merely withdrawing the screws 36, 38, and the interior of thelowercasing section I2 is freely accessible upon removal of the end plug46 and pin`47. The sled ISmay also be readily removed from the lowercasing base I2 by merely removing the cap screw39, thus permittingconvenient replacement of the rasp I5 with other reciprocatory impacttools.

From the foregoing detailed description it will be apparent that ourpresent invention provides an improved rportable i impact sunit and:ani111-,

However, Awhenever the roller "24 passes This entry of the provedto'oltherefor, which besides being simple. compact and ecient inconstruction, are readily manipulable in4 any desired position and incorners and other limited localities. All of the parts of the improveddriving mechanism are sturdy in construction and are so formed andoperable that they will transmit minimum jarring and vibration to theoperator manipulating the unit. The internal movable parts of theassemblage are thoroughly concealed and protected against possible entryof foreignmatter, while still being readily accessible for inspectionwith theaid-of ordinary tools, andthe improved rasp I5 while being'ofsimple and sturdy construction, is also highly effective in use and isnot susceptible of easy clogging.

The improved portable ling unit may be Aoperated either at high` or lowspeeds and has in fact been successfully operated at driving shaftspeeds of three thousand revolutions per minute, and the 1atches62, 63cooperate with the projection 30, socket 3I, plunger 6D and spring 59 toprovide simple but effective means for applying and for interrupting thepower. These latches also cooperate with the flexible conduit II topermit manipulation of the portable unit in any desired direction, andwhile the use of a flexible shaft 32 is not absolutely necessary, itwill permit cooperation of the portable unit with a stationary motor ofany suitable type. This motor While preferably being disposed in a fixed1ocality, may also be mounted directly -upon the portable unit. The unitis obviously extremely flexible in its adaptations and maybe operated inthe manner of an ordinary le or saw, and the invention has proven highlysatisfactory and successful in actual use, for ydiverse purposes. Theunit may also be manufactured and sold at moderate cost andhas'long lifedue to the fact that the working parts may be constantlyrmaintainedabundantly lubricated.

The specific construction of the file or rasp I5, and of the -mechanismfor imparting the impacts to this rasp, are important features of thepresent improvement, since it has heretofore been impossible to operatea rasp on soft metals without undesirable clogging of the teeth. Thesled I6 to which the rasp I5 is attached, is thoroughly guided duringits reciprocation, and the plunger 2U cooperating with the hexagonalsocket l5 of the hammer I8 provides efficient means for delivering theimpact or forward motions to the rasp I5. The relativelylight spring 42functions to return the plunger 2l] and the sled I6 without abnormalshock or vibration, and the heavy spring I9 functions to impart rapidimpulses to the hammer I8, While the buffer M absorbs the inertia of thehammer I8 at the end of each impact stroke. As previously indicated, thedriven member 2I may be formed with one or, more cam surfaces 22 anddrop-ofi surfaces 23 so that several impulses maybe delivered to thehammer I8 during each revolution of the member 2l. The rotating member2I should also be dynamically balanced in order to eliminate vibrationdue to unbalanced rotating parts, -and-in order to avoid subjecting theoperator to annoying disturbances. As previously indicated, theprovision of-a relatively heavy portable supporting body for thecomparatively light sled and tool, is an important feature of thepresent improvement, especially when applied to ling soft metals, and ithas been found that satisfactory filing of such metals cannot beaccomplished without 'having-the-casings IIL-I2 and the-ele- 9 mentsconfined therein of suicient combined weightJ so that the inertiathereof will prevent the chisel teeth from pushing the casings backwhenever an impact is applied to the tool. If such action did occur, thechisels would not be .impelled forwardly by the hammer, and there mustbe a decided and sharp hammer blow de livered to the tool in order toobtain most efflcient rasping or cutting. Our improved tool and casingassemblage most effectively accomplishes this desirable result and hasactually been utilized to eectively le various soft metals.

It should be understood that it is not desired to limit this inventionto the exact details of construction or to the precise mode of use,herein specifically shown and described, for various modificationswithin the scope of the appended claims may occur to persons skilled inthe art.

We claim:

l. A portable abrasive tool assemblage comprising, a casing havingtherein superimposed parallel upper and lower bores and also having arectilinear guide near an end oi the lower bore and a manipulatinghandle at the correspondingr end of the upper bore, a sled having acarrying plate for abrasive one end of which is slidably cooperable withsaid guide and the opposite end of which has an integral upstandingiiange extending over the opposite end of said lower bore, a plungerslidably conned within said lower bore and being detachably secured tosaid fiange to retain said plate within said guide, a hammerreciprocable within s-aid lower bore and being cooperable with saidplunger to impart impacts to said sled, a rotor revolvable within saidupper bore and being cooperable with said hammer to impart movementthereto in one direction, means for imparting impact motion to saidhammer in the opposite direction, and flexible motion transmitting meansextending longitudinally through said handle in alinement with saidupper bore for revolving said rotor.

2. A portable abrasive tool assemblage comprising, a casing havingsuperimposed sections each provided with an elongated bore, the lower ofsaid sections having a rectilinear guide near an end of its bore and theupper section having a manipulating handle projecting from thecorresponding end of its bore, a sled having a carrying plate forabrasive one end of which is slidably cooperable with said guide and theopposite end of which has a flange extending laterally of the plate overthe opposite end of said lower casing bore, a plunger slidably confinedwithin said lower section bore and being detachably secured to said angeto retain said plate within said guide, a hammer reciprocable withinsaid lower casing bore and being cooperable with said plunger to impartimpacts to said sled, a rotor revolvable within the upper section boreand being cooperable with said hammer to impart movement thereto in onedirection, a flexible motion transmitter extending longitudinallythrough said `handle in alinement with said rotor for revolving thelatter, and means within Said lower section bore for imparting impactmotion to said hammer in the opposite direction.

3. A portable abrasive tool assemblage comprising, a casing havingtherein superimposed parallel upper and lower bores the upper of whichis open at one end only and the lower of which is open at both ends, arectilinear guide associated with said casing near the end of said lowerbore nearest the open end of said upper bore, a sled having a carryingplate for abrasive one end of which is slidably cooperable with saidguide and the opposite end of which has a transverse flange extendingacross the opposite end of said lower bore, a plunger conned within saidlower bore and being detachably secured to said ange to retain saidplate within said guide, a hammer reciprocable within said lower boreand being cooperable with said plunger to impart impacts to said sled,means within said lower bore for moving said hammer in one direction, adetachable closure for the end of said lower bore remote from saidiiange for effecting insertion and removal of said plunger and hammerrelative to said bore, a rotor within said upper bore for moving saidhammer in the opposite direction, and a detachable closure for the openend of said upper bore for effecting insertion and removal of said rotorrelative to said bore.

SIEGMUND MANDL. EDWARD M. PFAUSER.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date 741,519 Mahaify Oct. 13, 1903807,143 Vernaz Dec. 12, 1905 1,063,076 Simmons May 27, 1913 1,356,297Lochner Oct. 19, 1920 1,458,439 Roberts June 12, 1923 1,588,832 YoungJune 15, 1926 1,798,082 Grutzbach Mar. 24, 1931 2,120,300 Taylor June14, 1938 2,123,426 Kehle July 12, 1938 2,197,626 Von Scheven Apr. 16,1940 2,307,431 Tilden et al Jan. 5, 1943 FOREIGN PATENTS Number CountryDate 5,859 Great Britain Mar. 8, 1911

